The present technology generally relates to venting systems for use with films that are suitable for use as, or with, food packaging. More specifically, the present technology relates to food packaging that includes, in certain embodiments, a freezable, microwaveable film layer having a venting system that facilitates the heating or cooking of hermetically packaged food contents at desirable temperatures and/or pressures.
In recent years, there has been an increase in the number of food products that are designed or intended to go directly from the freezer to the microwave for heating or cooking. Such food products often require packaging that also can go directly from freezer storage temperatures, typically temperatures ranging from about −20° C. to about 0° C., to microwave heating or cooking temperatures ranging from about 71° C. or greater. Additionally, it is desirable that such packaging perform without fracturing in the freezer, and without melting or bursting in the microwave. For example, with respect to foods such as vegetables, the temperatures reached during microwave cooking typically range from about 71° C. to about 105° C. However, when the packaged food items include meats, fish, grease, and/or oils, for example, the temperature of the items can reach up to about 150° C. when heated during microwave preparation.
Many freezable and microwaveable food packages can be made from, or include, a sealing film, such as the multilayered films discussed and disclosed in U.S. patent application Ser. Nos. 11/374,893 and 11/650,903, both of which are incorporated herein by reference in their entirety. Further, such films may be used for a variety of different types of food packages, which may have a variety of sizes and configurations. For example, a sealing film may be configured to form a pouch, wherein the sealing film is oriented to provide an inner region that is configured to receive the placement of a food product. Further, the edges of the sealing film may be sealed together so that the food product in the inner region is hermetically sealed. Other food packages may include a tray container having a base and sidewalls that form the inner region. The inner region of the tray container may also include one or more food compartments that receive the placement of food products. Often, the inner region of the tray container is covered by attaching a freezable, microwaveable sealing film to the top of the sidewalls or to a flange area so that the food product contained therein is hermetically sealed.
To ensure proper cooking of the food product in the microwave, and to prevent the food package from bursting, many existing freezable, microwaveable food packages require the inclusion of a vent for the cooking or heating cycle. More specifically, a vent may be added to the sealing film so as to release heat and/or steam that may be generated while cooking or heating the food product in the microwave.
Some freezable, microwaveable food packages do not include a steam vent system, but instead rely on the user to create the vent by piercing a slot or hole into the sealing film prior to placing the food package into the microwave.
Other types of freezable, microwaveable food packages include built-in steam venting systems. For example, a food package may have built-in holes or slits on the sides or end seals of the sealing film that may be formed by mechanical apparatuses, such as cutters or punches. Additionally, some food packages may have vent systems in the form of micro-perforated zones or strips in the sealing film. In some instances, such slits or openings may be formed in a portion of a food package and is subsequently covered or closed by the addition of a laminate to the food package.
Some freezable, microwaveable food packages provide a built-in vent by scoring a line across most, if not all, the length of the sealing film of the food package to create a line where the film may tear during the cooking operation. For example, some food packages may use an approximately 6 inch (15 cm) long scored line across nearly the entire length of a freezable, microwaveable food package that is in the form of a pouch. Moreover, this scored line may extend from approximately one seam or edge to the opposite seam or edge of the package.